Dell Desktop Wireless Connection

Desktop Internet works, Wireless does not … = [?

ok so I installed a fresh copy of xp home and installed it to my mother and all the drivers for the graphics. (built own pc) I called the provider (att internet, modem Motorola-silver one http://ecx.images-amazon.com/images/I/31qt3QoqXOL._SL500_AA280_.jpg) and they said I had to contact Linksys (my router). After talking with the coach, he said that I would be charged $ 40. I do not have $ 40 to spend on some stupid sob. I told him to call back in an hour for my decision (I was researching some corrections and suggestions), and well, never called figures out … Wall leave it on the modem, modem connected to Linksys, linksys connected to the PC. i have this custom desktop, a Toshiba portable computer (internet wireless), and a Dell desktop (wireless internet) all those internet connections worked before I talked to ATT and blew it = [Please help me. Ps-lnksys wrt54g

http://www.google.co.in/search?q=how+to+setup+wireless&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a

Updated Server Room & network DSL connection